This invention relates to joints and in particular to joints and hand tools for connecting a pipe or other tubular elements to a hollow structure having a tubular inlet thereto.
Joints of the type with which this invention is concerned have many applications, examples being joints for use in connection with central heating systems, air conditioning systems, vehicles, white goods, petrol pumps, fire fighting equipment, heater batteries, tank fittings and three way valve systems.
Current joints of the type with which this invention is concerned are normally such that they are difficult to install and a major reason for this is that they do not allow relative axial movement between the pipe and the hollow structure to which the pipe is to be connected.
According to the present invention there is provided a method of interconnecting an end of a pipe with a hollow structure having a screw-threaded tubular inlet thereto, the method comprising applying an annular sealing member around the pipe, said annular sealing member having a screw-threaded portion for engagement with the screw-threaded tubular inlet and being provided with first and second sealing means, said first sealing means being for sealing engagement between said annular sealing member and said inlet and said second sealing means being for sealing engagement between said annular sealing member and said pipe end, distorting outwardly the end of the pipe around at least a portion of the periphery thereof, and effecting screw-threaded engagement between the annular sealing member and the tubular inlet, whereby sealing engagement may be effected between said sealing member and said pipe and over a plurality of relative axial positions therebetween.
Accordingly, a joint formed by a method allows relative axial movement between the members to be joined together. Such an arrangement allows easy positioning of the members into their appropriate positions relative to each other and subsequent operation to form an effective joint between the members.
The annular sealing member is a single member provided with means for accommodating the first and second sealing means as well as a screw threaded portion or other means for engaging the tubular inlet. The annular sealing member may also be provided with a recess so as to accommodate a protrusion or crimp or upset of a pipe. The recess is preferably substantially continuous about the periphery of the pipe.
The first and second sealing means may be any suitable sealing elements, for instance, O-rings.
The sealing member and the pipe may be put into sealing engagement with each other over a plurality of discrete relative axial positions or over a continuous range of positions therebetween. Preferably, the pipe is provided with some form of radially and outwardly extending protrusion which limits the range of axial positions due to engagement between said protrusion and another element of the joint, for instance, the annular sealing member.
In another embodiment of the invention the pipes provided with two radially and outwardly extending protrusions. Preferably, the first of said protrusions protrudes a sufficient distance about the periphery of a pipe so as to engage with the joint of the invention and prevent the pipe from being pulled out of engagement with same. More preferably said first protrusion is suitable located a relatively short distance from the end of the pipe. Preferably, the second protrusion is relatively small with respect to the first protrusion, and more preferably still said second protrusion is of marginally smaller dimensions than the recess portion in the annular sealing member. Thus, in use and in position, said second protrusion is accommodated within the recess portion of the annular sealing member and is allowed sufficient movement therein so as not to impede rotational movement of the pipe.
It will be appreciated that provision of two protrusions, the first protrusion acting as a pipe-stop just outside the joint itself, and the second protrusion being loosely accommodated within the joint itself, allows for limited axial movement whilst providing a secure joint.
The invention also provides a joint for use in the method of the invention, the joint being as defined above in connection with said method.
There may also be provided with the joint a tool comprising means for distorting or crimping or flaring the end of a pipe. Ideally the tool is manually operated and the tool may be of a scissors type or a clamping type action. In the scissors type embodiment, the tool comprises pivotally connected upper and lower jaws, wherein the lower jaw has corresponding recesses into which spikes or ribs of the upper jaw fit when the jaws are closed together about at least a part of a pipe. Alternatively the tool comprises a clamp, wherein an upper surface of said clamp is provided with recess portions and a lower surface is provided with corresponding spikes or ridges or the like which fit into the recesses in a clamped position. In use, the pipe is sandwiched between the two clamping surfaces or scissors jaws and sufficient force is applied so as to impart a crimp or ridge or groove onto the pipe surface.